A polyrotaxane, which is comprised of a pseudopolyrotaxane, which comprises a linear molecule and cyclic molecules in which the linear molecule is included in cavities of cyclic molecules in a skewered manner, and capping groups, each of which locates at each end of the pseudopolyrotaxane in order to prevent the dissociation of the cyclic molecules, has characteristics originating from the relative movement of the cyclic molecule(s) along the linear molecule, and is therefore expected to be useful in various applications (see Patent Document 1).
For example, Patent Document 2 discloses a material comprising a polyrotaxane and a polymer, wherein at least apart of the polyrotaxane and the polymer are bound to each other via a cyclic molecule(s). It is disclosed that the material has superior viscoelasticity, but that the material only provides the viscoelasticity when water is included in the material as solvent.
Further, Patent Document 3 discloses a polyrotaxane, which has a hydrolyzable (biodegradable) property and also is introduced with a biocompatible group, and its crosslinked body (hydrogel). It is disclosed that the crosslinked body (hydrogel) contains water as a solvent, but no description is included regarding viscoelasticity.
Patent Document 4 discloses a polyurethane elastomer having a rotaxane structure in which a linear diol is introduced to a crown ether ring. However, the polyurethane elastomer does not have either the polyrotaxane structure or the crosslinked polyrotaxane structure.
Non-Patent Document 1 discloses that an elastomer is obtained by crosslinking a polycaprolactone-modified polyrotaxane with hexamethylene diisocyanate and removing the solvent. However, as the elastomer exhibits relatively high stress characteristics as stress-strain characteristics, only insufficient characteristics are shown for an application which requires viscoelasticity with higher flexibility.